This application relates to a coated article including an anti-reflective layer(s) system. The anti-reflective layer(s) system may include one or more layers.
Coated articles are known in the art. For example, U.S. Pat. No. 5,800,933 discloses a coated article with a solar controlling layer system. The ""933 coated article includes: substrate/TiO2/Si3N4/NiCr/Ag/NiCr/Si3N4. For example, see FIG. 1 of the instant application. In such coatings, the NiCr contact layers function to protect the Ag (silver) layer and also serve as adhesion and/or nucleation layers. The dielectric layers (i.e., TiO2, Si3N4) serve protective functions and also perform anti-reflection functions (i.e., they reduce visible reflectance), and as a result serve to increase transmission of the overall coated article. Other prior art coatings are similar to that shown in FIG. 1, but omit the TiO2 layer.
While coated articles such as that shown in FIG. 1 provide good ultraviolet (UV) and/or infrared (IR) reflection, they do face problems. Such problems often relate to meeting high visible transmission requirements imposed by industry standards and/or markets, while simultaneously satisfying UV and/or IR needs. The need for higher visible transmission often forces coating designers to minimize contact layer thicknesses and/or change contact layer materials to less absorbing and/or less durable options. The unfortunate consequence may be marginal durability of the coated article if high transmission requirements are to be met. In other words, it would be desirable if visible transmission of such articles could be increased and/or if visible reflection of such articles could be reduced while maintaining good durability.
Neutral color is also desirable for coated articles in many applications. Unfortunately, many conventional methods of making color of a coated article more neutral result in decreased visible transmission and/or increased reflection. Heretofore, it has been difficult to increase visible transmission and reduce reflection, while at the same time providing more neutral color and maintaining satisfactory solar control or thermal characteristics.
In view of the above, it is an object of certain embodiments of this invention to provide a solar controlling coated article (i.e., an article including at least one layer for reflecting IR and/or UV) having increased visible transmission and/or reduced visible reflectance. In certain embodiments of this invention, it is an object to combine such high visible transmission and/or reduced reflectance with neutral color of the coated article. One or more of these objects is/are achieved by providing such coated articles with improved anti-reflection layer(s) system(s). Alternatively, the use of such improved anti-reflection layer(s) system(s) may enable coatings to have or utilize more robust contact layer(s) (e.g., thicker for better durability) and/or thicker silver (Ag) layer(s) (i.e., improved thermal performance) while maintaining similar transmission characteristics if increased transmission is not a most desired feature.
Another object of this invention is to fulfill one or more of the above-listed objects and/or needs.
In certain example non-limiting embodiments of this invention, one or more of the above-listed objects and/or needs is/are satisfied by providing a coated article including a coating supported by a glass substrate, the coating comprising: a metallic infrared (IR) reflecting layer sandwiched between first and second contact layers; a first dielectric layer having an index of refraction n less than =2.7 (note: all indices of refraction xe2x80x9cnxe2x80x9d herein are at 550 nm) provided between the IR reflecting layer and the glass substrate; a second dielectric layer comprising titanium oxide provided over the IR reflecting layer; a third dielectric layer comprising silicon oxynitride provided over the IR reflecting layer; a fourth dielectric layer comprising silicon oxide provided over the IR reflecting layer; and wherein the third dielectric layer comprising silicon oxynitride is provided between the second and fourth dielectric layers.
In other example non-limiting embodiments of this invention, one or more of the above-listed objects and/or needs is/are satisfied by providing a coated article including a coating supported by a glass substrate, the coating comprising: a metallic infrared (IR) reflecting layer comprising silver sandwiched between first and second contact layers each of which contacts the IR reflecting layer; a first dielectric layer having an index of refraction n less than =3.0 provided between the IR reflecting layer and the glass substrate; a second dielectric layer comprising silicon oxynitride provided over the IR reflecting layer; a third dielectric layer comprising silicon oxide provided over the IR reflecting layer; and wherein the second dielectric layer comprising silicon oxynitride is provided between the IR reflecting layer and the third dielectric layer comprising silicon oxide. Optionally, another dielectric layer comprising silicon nitride may be provided between the IR reflecting layer and the silicon oxynitride layer.
Certain other example non-limiting embodiments of this invention fulfill one or more of the above-listed objects and/or needs by providing a coated article including a coating supported by a glass substrate, the coating comprising: a metallic infrared (IR) reflecting layer sandwiched between first and second contact layers which contact the IR reflecting layer; a first dielectric layer having an index of refraction n less than =3.0 provided between the IR reflecting layer and the glass substrate; a second dielectric layer comprising titanium oxide provided over the IR reflecting layer; a third dielectric layer comprising silicon oxide provided over the IR reflecting layer; and wherein the second dielectric layer comprising titanium oxide is provided between the IR reflecting layer and the third dielectric layer comprising silicon oxide.
In certain example non-limiting embodiments of this invention, silicon oxynitride layer(s) may be graded (oxidation graded and/or nitrogen graded) so as to vary their respective indices of refraction n throughout their thickness(es) in a desired manner. Moreover, titanium oxide layer(s) herein may be index graded (to change the index of refraction) by changing the microstructure of the layer throughout its thickness. For example, the index of refraction n of titanium oxide can vary as a function of crystalline structure and/or packing density in the layer; and such microstructure changes can be caused by pressure adjustments, substrate temperatures, post-treatment (e.g., heat treatment), deposition rate, angle of incidence, and/or substrate surface conditions.
Certain other example non-limiting embodiments of this invention fulfill one or more of the above-listed objects and/or needs by providing a coated article including a coating supported by a substrate, the coating comprising: a layer comprising Ag located between first and second contact layers which contact the layer comprising Ag; a first dielectric layer having an index of refraction n less than =3.0 provided between the substrate and the layer comprising Ag; a second dielectric layer having an index of refraction n=2.1-2.7 provided over the layer comprising Ag; a third dielectric layer having an index of refraction n=1.4-1.7 (more preferably n=1.4 to 1.5) provided over the layer comprising Ag and over the second dielectric layer; and wherein the coated article has a visible transmission of at least 70%, a sheet resistance (Rs) less than =20 ohms/sq., and color characterized by a transmissive a* value from xe2x88x924.0 to +2.0, a transmissive b* value from xe2x88x925.0 to +3.0, a glass side reflective a* value from xe2x88x924.0 to +3.0, and a glass side reflective b* value from xe2x88x926.0 to +4.0.